Metathesis polymers as dielectrics

ABSTRACT

Oxacycloolefinic polymers as typically obtained by metathesis polymerization using Ru-catalysts, show good solubility and are well suitable as dielectric material in electronic devices such as capacitors and organic field effect transistors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage application (under 35 U.S.C. §371)of PCT/EP2014/063113, filed Jun. 23, 2014, which claims benefit ofEuropean Application No. 13174013.6, filed Jun. 27, 2013, both of whichare incorporated herein by reference in their entirety.

The present invention relates to a process for the preparation of anorganic electronic device, such as a capacitor or transistor on asubstrate, to the device obtainable by that process, to certainoxacycloolefinic polymers and their use as dielectrics, especially asdielectric layer in printed electronic devices such as capacitors andorganic field-effect transistors (OFETs).

Transistors, and in particular OFETs, are used e.g. as components forprinted electronic devices such as organic light emitting display,e-paper, liquid crystal display and radiofrequency identification tags.

An organic field effect transistor (OFET) comprises a semiconductinglayer comprising an organic semiconducting material, a dielectric layercomprising a dielectric material, a gate electrode and source/drainelectrodes.

Especially desirable are OFETs wherein the dielectric material can beapplied by solution processing techniques. Solution processingtechniques are convenient from the point of processability, and can alsobe applied to plastic substrates. Thus, organic dielectric materials,which are compatible with solution processing techniques, allow theproduction of low cost organic field effect transistors on flexiblesubstrates.

Oxanorbornene dicarboximides have been polymerized by ring openingmetathesis polymerization (ROMP) to obtain amorphous polymers (Cetinkayaet al., Heteroatom Chemistry (2010), 21, 36-43), or copolymers withtunable magnetic properties (Zha et al., J. Am. Chem. Soc. (2012), 134,14534).

WO 12/028278 and US 2008/194740 disclose certain layers comprising acycloolefinic polymer prepared by Ni-catalysis. WO 12/028279 disclosesthe same type of polymer for use as a gate dielectric layer in contactwith a semiconductor layer.

It is the object of the present invention to provide a dielectricmaterial which allows easy solution processing while resulting in gooddielectric properties and adherence.

It has now been found that oxacycloolefinic polymers, as typicallyobtained by Ru-carbene catalyzed ring-opening metathesis polymerizationof a bicyclic oxaolefin, show such advantageous properties as adielectric material.

The present invention thus primarily pertains to an electronic devicecontaining at least one dielectric material which comprises anoxacycloolefinic polymer.

A further advantage of the present dielectric comprising anoxacycloolefinic polymer is its solubility in rather polar solvents,which property allows for solvent processing upon previous layer(s) ofmaterial (e.g. organic semiconductors), which show low tendency todissolve in such media.

Ru-carbenes and their use as catalysts in the metathesis polymerizationreaction have been widely described in literature, see e.g. U.S. Pat.Nos. 6,407,190, 6,465,554 and publications cited therein (e.g. column 1,lines 9-37 of U.S. Pat. No. 6,465,554); U.S. Pat. No. 7,037,993 (e.g.column 11, line 34, to col. 13 line 10); and references cited furtherabove; examples are bis(tricyclohexylphosphine)benzylidine ruthenium(IV)dichloride,

The educt for metathesis polymerization is generally described as astrained cycloolefin, typically a bicyclic olefin such as norbornene(bicyclo[2.2.1]hept-2-ene), which may be unsubstituted or substituted.The type of catalyst thereby determines the type of polymer chainobtained; Ni-catalysts generally lead to polymer chains wherein theoriginal bicyclic structure of the monomer is maintained and the polymerbonds are formed by the former olefinic double bonds. The presentRuthenium carbene catalysts lead to the opening of one ring withformation of a polymer chain containing olefinic double bonds in theirnon-cyclic parts, as apparent from the below scheme:

wherein n denotes the number of repeating units within the polymer chainand “Ru” stands for the Ru-carbene catalyst to be used in accordancewith the present invention.

The oxacycloolefinic polymer is, consequently, obtained by Ru-carbenecatalyzed polymerization of a bicyclic oxaolefin. “Oxa” therein denotesan oxygen atom replacing a CH2-moiety within the bicyclic ring system ofa bicycloolefin. Typical example is a norbornene, wherein one CH2 hasbeen replaced by oxygen, thus conforming to the structurebicyclo[2.2.1]-5-oxa-hept-2-ene, bicyclo[2.2.1]-6-oxa-hept-2-ene orbicyclo[2.2.1]-7-oxa-hept-2-ene, each of which may be unsubstituted orsubstituted. A preferred example for such an educt is an oxanorborneneof the formula I

whereineach of R₁ to R₆ are selected from hydrogen and C₁-C₄alkyl; and R₇ andR₈ are hydrogen or a substituent; or R₇ and R₈ form, together with thecarbon atoms they are attached to, a saturated or unsaturatedcarbocyclic ring of 5 to 12 carbon atoms, which is unsubstituted orsubstituted, or a saturated or unsaturated ring comprising 4 to 11carbon atoms and 1 or 2 oxygen atoms or groups NR₉, with R₉ beinghydrogen or a substituent, as ring members, which ring is unsubstitutedor substituted.

The electronic device according to the present invention thus typicallycomprises an oxacycloolefinic polymer of the formula II

wherein n ranges from 3 to 100 000, and each of R₁ to R₈ are as definedfor formula I above. More preferably, the oxacycloolefinic polymercomprises a polymer chain of the formula III

wherein each of n and R2 to R5 are as defined above, and

R is hydrogen, C1-C25alkyl, C1-C25haloalkyl, phenyl, phenyl-C1-C4alkyl,cyclopentyl, cyclohexyl, wherein phenyl moiety or cyclopentyl orcyclohexyl moiety itself is unsubstituted or substituted by C1-C4alkyl,C1-C4alkoxy, OH, halogen.

The electronic device according to the present invention usually isselected from capacitors, transistors such as organic field effecttransistors, and devices comprising said capacitor and/or transistor; itcontains the oxacycloolefinic polymer preferably as a capacitor layer orgate insulating layer, typically as part of an organic thin filmtransistor such as an OFET, thus making use of its superior dielectricproperties.

Any substituent, whenever mentioned, is typically selected from halogen,C1-C25alkyl, C2-C25alkenyl, C1-C25alkylthio, C1-C25alkoxy,C2-C25alkenyloxy, C4-C10aryl, C1-C9heteroaryl, C3-C12cycloalkyl,C2-C11heterocycloalkyl, each of which is unsubstituted or substituted byR′; or is C2-C25alkyl, C3-C25alkenyl, C2-C25alkylthio, C2-C25alkoxy,C3-C25alkenyloxy, which is interrupted in its alkyl part by O, CO, COO,CONR, CONRCO, S, SO, SO2, NR, and is unsubstituted or substituted by R′;or is selected from the residues OR, COR, CH═NR, CH═N—OH, CH═N—OR, COOR,CONHR, CONRR′, CONH—NHR, CONH—NRR′, SO2R, SO3R, SO2NHR, SO2NRR′,SO2NH—NHR, SO2NH—NRR′, S(O)R, S(O)OR, S(O)NHR, S(O)NRR′, S(O)NH—NHR,S(O)NH—NRR′, SiRR′R″, PORR′, PO(OR)R′, PO(OR)2, PO(NHR)2, PO(NRR′)2, CN,NO2, NHR, NRR′, NH—NHR, NH—NRR′, CONROH; and if bonding to saturatedcarbon may also be oxo;

and wherein R, R′ and R″ independently are selected from C1-C25alkyl,C1-C25haloalkyl, C5-C10aryl, C6-C12arylalkyl, C3-C12cycloalkyl,preferably from C1-C6alkyl, phenyl, benzyl, cyclopentyl, cyclohexyl; andR may also be hydrogen;

where each aryl or heteroaryl or cycloalkyl itself is unsubstituted orsubstituted by C1-C4alkyl, C2-C4alkenyl, C1-C4alkoxy, OH, CHO,C1-C4alkyl-carbonyl, C1-C4alkyl-carbonyloxy, C1-C4alkoxy-carbonyl,allyloxy, halogen.

The invention thus pertains to an electronic device, generally anorganic electronic device, as it may be prepared in a printing processon a substrate. The substrate may be glass, but is typically a plasticfilm or sheet. Typical devices are capacitors, transistors such as anelectronic field effect transistor (OFET), or devices comprising saidcapacitor and/or transistor. The device of the invention contains atleast one dielectric material, usually in the form of a dielectriclayer, which comprises the present oxacycloolefinic polymer. The deviceof the invention generally contains at least one further layer of afunctional material, mainly selected from conductors and semiconductors,which usually stands in direct contact with the present oxacycloolefinicpolymer dielectric material or layer; examples are OFETs containing thelayer of dielectric material according to the invention in directcontact with the electrode and/or the semiconductor.

Present invention further provides a process for the preparation of anelectronic device, such as a capacitor or transistor on a substrate,which process comprises the steps of

-   -   i) providing a solution or dispersion of an oxacycloolefinic        polymer, as described above, in a suitable solvent, and    -   ii) forming a layer on a substrate, an electrode material and/or        a semiconductor, and drying said layer.

Preferably, the process does not comprise a step of heat treatment at atemperature of >=150° C., More preferably, the process does not comprisea step of heat treatment at a temperature of >=140° C. Most preferably,the process does not comprise a step of heat treatment at a temperatureof >=120° C. Accordingly, the heat treatment in step (ii), if present,usually requires heating the layer to a temperature from the range 30 to150° C., preferably 40 to 140° C., especially 50 to 120° C.

Suitable as the solvent (hereinbelow also recalled as organic solvent A)is any solvent (or solvent mixture), which is able to dissolve at least2% by weight, preferably at least 5% by weight, more preferably, atleast 8% by weight of the oxacycloolefinic polymer.

As the organic solvent A, generally any solvent may be chosen which hasa boiling point (at ambient pressure) from the range of about 80 to 250°C. Solvent A may be a mixture of such solvents. In a preferred process,any component of solvent A has a boiling point from the range 100-220°C., especially 100-200° C. Also of importance are blends using a mainsolvent (e.g. 70% b.w. or more, such as 95%) having a boiling pointaround 150° C. (e.g. 120 to 180° C.) and a minor component (30% b.w. orless, such as 5%) having a high boiling point of more than 200° C., e.g.from the range 200-250° C.

Preferably, the organic solvent A is selected from the group consistingof N-methylpyrrolidone, C₄₋₈-cycloalkanone, C₁₋₄-alkyl-C(O)—C₁₋₄-alkyl,C₁₋₄-alkanoic acid C₁₋₄-alkyl ester, wherein the C₁₋₄-alkyl or theC₁₋₄-alkanoic acid can be substituted by hydroxyl or O—C₁₋₄-alkyl, andC₁₋₄-alkyl-O—C₁₋₄-alkylene-O—C₁₋₄-alkylene-O—C₁₋₄-alkyl, and mixturesthereof.

Examples of C₁₋₄-alkyl-C(O)—C₁₋₄-alkyl are ethyl isopropyl ketone,methyl ethyl ketone and methyl isobutyl ketone.

Examples of C₁₋₄-alkanoic acid C₁₋₄-alkyl ester, wherein the C₁₋₄-alkylor the C₁₋₄-alkanoic acid can be substituted by hydroxyl orO—C₁₋₄-alkyl, are ethyl acetate, butyl acetate, isobutyl acetate,(2-methoxy)ethyl acetate, (2-methoxy)propyl acetate and ethyl lactate.

An example of C₁₋₄-alkyl-O—C₁₋₄-alkylene-O—C₁₋₄-alkylene-O—C₁₋₄-alkyl isdiethyleneglycoldimethylether.

More preferably, the organic solvent A is selected from the groupconsisting of C₄₋₈-cycloalkanone, C₁₋₄-alkyl-C(O)—C₁₋₄-alkyl,C₁₋₄-alkanoic acid C₁₋₄-alkyl ester, wherein the C₁₋₄-alkyl or theC₁₋₄-alkanoic acid can be substituted by hydroxyl or O—C₁₋₄-alkyl, andC₁₋₄-alkyl-O—C₁₋₄-alkylene-O—C₁₋₄-alkylene-O—C₁₋₄-alkyl, and mixturesthereof. Examples are methyl ethyl ketone (b.p. 80° C.), 1,4-dioxane,methyl-isobutyl ketone, butylacetate, 2-hexanone, 3-hexanone,2-methoxy-1,3-dioxolane, Propylene glycol methyl ether acetate (PGMEA),ethyl lactate, DiGlyme, 5-methyl-3H-furan-2-one (b.p. 169° C.[“alpha-angelica lactone”]), dipropylene glycol dimethyl ether (b.p.175° C. [ProGlyde DMM]), N-methylpyrrolidone (NMP), gamma-butyrolactone,acetophenone, isophorone, gamma-aprolactone, 1,2-propylene carbonate(b.p. 241° C.); blends of Propylene glycol methyl ether acetate (PGMEA,b.p. 145° C., e.g. 95%) and proyplene carbonate (e.g. 5%).

Most preferably, the organic solvent A is selected from the groupconsisting of C₅₋₆-cycloalkanone, C₁₋₄-alkanoic acid C₁₋₄-alkyl ester,and mixtures thereof. Even most preferably the organic solvent A iscyclopentanone or PGMEA or mixtures thereof. In particular preferredorganic solvents A are PGMEA or mixtures of PGMEA and pentanone, whereinthe weight ratio of PGMEA/cyclopentanone is at least from 99/1 to 20/80,more preferably from 99/1 to 30/70.

If the oxacycloolefinic polymer is applied as a solution in an organicsolvent A on the layer of the transistor or on the substrate, theoxacycloolefinic polymer can be applied by any possible solutionprocess, such as spin-coating, drop-casting or printing.

After applying oxacycloolefinic polymer as a solution in an organicsolvent A on the layer of the transistor or on the substrate, a heattreatment at a temperature of below 140° C., for example at atemperature in the range of 60 to 120° C., preferably at a temperatureof below 120° C., for example in the range of 60 to 110° C. can beperformed.

The layer comprising oxacycloolefinic polymer can have a thickness inthe range of 100 to 1000 nm, preferably, in the range of 300 to 1000 nm,more preferably 300 to 700 nm.

The layer comprising oxacycloolefinic polymer can comprise from 50 to100% by weight, preferably from 80 to 100%, preferably 90 to 100% byweight of oxacycloolefinic polymer based on the weight of the layercomprising oxacycloolefinic polymer. Preferably, the layer comprisingoxacycloolefinic polymer essentially consists of oxacycloolefinicpolymer.

Examples of aromatic rings are phenyl and naphthyl. Phenyl is preferred.

Examples of halogen are fluoro, chloro and bromo.

Examples of C₁₋₁₀-alkyl are methyl, ethyl, propyl, isopropyl, butyl,sec-butyl, isobutyl, tert-butyl, pentyl, 2-ethylbutyl, hexyl, heptyl,octyl, nonyl and decyl. Examples of propyl and butyl are n-propyl,isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl.

Examples of C₄₋₈-cycloalkyl are cyclobutyl, cyclopentyl, cyclohexyl,cycloheptyl and cyclooctyl.

Examples of C₁₋₁₀-haloalkyl are trifluoromethyl and pentafluoroethyl.

Examples of C₂₋₁₀-alkenyl are vinyl, CH₂—CH═CH₂, CH₂—CH₂—CH═CH₂.

Examples of C₄₋₁₀-cycloalkenyl are cyclopentyl, cyclohexyl andnorbornenyl.

Examples of C₁₋₁₀-alkylene are methylene, ethylene, propylene, butylene,pentylene, hexylene and heptylene. Examples of C₁₋₄-alkylene aremethylene, ethylene, propylene and butylene

Examples of C₄₋₈-cycloalkylene are cyclobutylene, cyclopentylene,cyclohexylene and cycloheptylene.

Examples of C₁₋₄-alkanoic acid are acetic acid, propionic acid andbutyric acid.

The glass transition temperature of the present oxacycloolefinicpolymer, as determined by differential scanning calorimetry, ispreferably above 90° C., more preferably above 130° C., and morepreferably between 150° C. and 300° C.

The molecular weight of the oxacycloolefinic polymer can be in the rangeof 5000 to 2000000 g/mol, preferably 10000 to 1000000 g/mol (asdetermined by gel permeation chromatography).

The transistor on a substrate is preferably a field-effect transistor(FET) on a substrate and more preferably an organic field-effecttransistor (OFET) on a substrate.

Usually, an organic field effect transistor comprises a dielectric layerand a semiconducting layer. In addition, on organic field effecttransistor usually comprises a gate electrode and source/drainelectrodes.

Typical designs of organic field effect transistors are the Bottom-Gatedesign and the Top-Gate design:

In case of the Bottom-Gate Bottom-Contact (BGBC) design, the gate is ontop of the substrate and at the bottom of the dielectric layer, thesemiconducting layer is at the top of the dielectric layer and thesource/drain electrodes are on top of the semiconducting layer.

Another design of a field-effect transistor on a substrate is theTop-Gate Bottom-Contact (TGBC) design: The source/drain electrodes areon top of the substrate and at the bottom of the semiconducting layer,the dielectric layer is on top of the disemiconducting layer and thegate electrode is on top of the dielectric layer. When prepared bysolution processing, here the solvents used for dielectrics must befully orthogonal with respect to the semiconductor (i.e. show goodsolubility of the dielectric and absolute insolubility of thesemiconductor), and additionally compatible with photoresist processing.

The semiconducting layer comprises a semiconducting material. Examplesof semiconducting materials are semiconducting materials having p-typeconductivity (carrier: holes) and semiconducting materials having n-typeconductivity (carrier: electrons).

Examples of semiconductors having n-type conductivity areperylenediimides, naphtalenediimides and fullerenes.

Semiconducting materials having p-type conductivity are preferred.Examples of semiconducting materials having p-type conductivity aremolecules such as as rubrene, tetracene, pentacene,6,13-bis(triisopropylethynyl) pentacene, diindenoperylene,perylenediimide and tetracyanoquinodimethane, and polymers such aspolythiophenes, in particular poly 3-hexylthiophene (P3HT),polyfluorene, polydiacetylene, poly 2,5-thienylene vinylene, polyp-phenylene vinylene (PPV) and polymers comprising repeating unitshaving a diketopyrrolopyrrole group (DPP polymers).

Preferably the semiconducting material is a polymer comprising unitshaving a diketopyrrolopyrrole group (DPP polymer).

Examples of DPP polymers and their synthesis are, for example, describedin U.S. Pat. No. 6,451,459 B1, WO 2005/049695, WO 2008/000664, WO2010/049321, WO 2010/049323, WO 2010/108873, WO 2010/115767, WO2010/136353 and WO 2010/136352.

Preferably, the DPP polymer comprises, preferably essentially consists,of a unit selected from the group consisting of

a polymer unit of formula

a copolymer unit of formula

a copolymer unit of formula

anda copolymer unit of formula

wherein

-   n′ is 4 to 1000, preferably 4 to 200, more preferably 5 to 100,-   x′ is 0.995 to 0.005, preferably x′ is 0.2 to 0.8,-   y′ is 0.005 to 0.995, preferably y′ is 0.8 to 0.2, and-   x′+y′=1;-   r′ is 0.985 to 0.005,-   s′ is 0.005 to 0.985,-   t′ is 0.005 to 0.985,-   u′ is 0.005 to 0.985, and-   r′+s′+t′+u′=1;

A is a group of formula

-   -   wherein    -   a″ is 1, 2, or 3,    -   a′″ is 0, 1, 2, or 3,    -   b′ is 0, 1, 2, or 3,    -   b″ is 0, 1, 2, or 3,    -   c′ is 0, 1, 2, or 3,    -   c″ is 0, 1, 2, or 3,    -   d′ is 0, 1, 2, or 3,    -   d″ is 0, 1, 2, or 3,    -   with the proviso that b″ is not 0, if a′″ is 0;    -   R⁴⁰ and R⁴¹ are the same or different and are selected from the        group consisting of hydrogen, C₁-C₁₀₀alkyl, —COOR^(106″),        C₁-C₁₀₀alkyl which is substituted with one or more halogen,        hydroxyl, nitro, —CN, or C₆-C₁₈aryl and/or interrupted by —O—,        —COO—, —OCO—, or —S—; C₇-C₁₀₀arylalkyl, carbamoyl,        C₅-C₁₂cycloalkyl, which can be substituted one to three times        with C₁-C₈alkyl and/or C₁-C₈alkoxy, C₆-C₂₄aryl, in particular        phenyl or 1- or 2-naphthyl which can be substituted one to three        times with C₁-C₈alkyl, C₁-C₂₅thioalkoxy, and/or C₁-C₂₅alkoxy, or        pentafluorophenyl, wherein        -   R^(106″) is C₁-C₅₀alkyl, preferably C₄-C₂₅alkyl,    -   Ar¹, Ar^(1′),Ar², Ar^(2′), Ar³, Ar^(3′), Ar⁴ and Ar^(4′) are        independently of each other heteroaromatic, or aromatic rings,        which optionally can be condensed and/or substituted, preferably

-   -   wherein    -   one of X³ and X⁴ is N and the other is CR⁹⁹,        -   wherein R⁹⁹ is hydrogen, halogen, preferably F, or            C₁-C₂₅alkyl, preferably a C₄-C₂₅alkyl, which may optionally            be interrupted by one or more oxygen or sulphur atoms,            C₇-C₂₅arylalkyl, or C₁-C₂₅alkoxy,    -   R¹⁰⁴, R^(104′), R¹²³ and R^(123′) are independently of each        other hydrogen, halogen, preferably F, or C₁-C₂₅alkyl,        preferably a C₄-C₂₅alkyl, which may optionally be interrupted by        one or more oxygen or sulphur atoms, C₇-C₂₅arylalkyl, or        C₁-C₂₅alkoxy,    -   R¹⁰⁵, R^(105′), R¹⁰⁶ and R^(106′) are independently of each        other hydrogen, halogen, C₁-C₂₅alkyl, which may optionally be        interrupted by one or more oxygen or sulphur atoms;        C₇-C₂₅arylalkyl, or C₁-C₁₈alkoxy,    -   R¹⁰⁷ is C₇-C₂₅arylalkyl, C₆-C₁₈aryl; C₆-C₁₈aryl which is        substituted by C₁-C₁₈alkyl, C₁-C₁₈perfluoroalkyl, or        C₁-C₁₈alkoxy; C₁-C₁₈alkyl; C₁-C₁₈alkyl which is interrupted by        —O—, or —S—; or —COOR¹²⁴;        -   R¹²⁴ is C₁-C₂₅alkyl, preferably C₄-C₂₅alkyl, which may            optionally be interrupted by one or more oxygen or sulphur            atoms, C₇-C₂₅arylalkyl,    -   R¹⁰⁸ and R¹⁰⁹ are independently of each other H, C₁-C₂₅alkyl,        C₁-C₂₅alkyl which is substituted by E′ and/or interrupted by D′,        C₇-C₂₅arylalkyl, C₆-C₂₄aryl, C₆-C₂₄aryl which is substituted by        G, C₂-C₂₀heteroaryl, C₂-C₂₀heteroaryl which is substituted by G,        C₂-C₁₈alkenyl, C₂-C₁₈alkynyl, C₁-C₁₈alkoxy, C₁-C₁₈alkoxy which        is substituted by E′ and/or interrupted by D′, or C₇-C₂₅aralkyl,        or    -   R¹⁰⁸ and R¹⁰⁹ together form a group of formula ═CR¹¹⁰R¹¹¹,        wherein        -   R¹¹⁰ and R¹¹¹ are independently of each other H,            C₁-C₁₈alkyl, C₁-C₁₈alkyl which is substituted by E′ and/or            interrupted by D′, C₆-C₂₄aryl, C₆-C₂₄aryl which is            substituted by G, or C₂-C₂₀heteroaryl, or C₂-C₂₀heteroaryl            which is substituted by G,    -   or    -   R¹⁰⁸ and R¹⁰⁹ together form a five or six membered ring, which        optionally can be substituted by C₁-C₁₈alkyl, C₁-C₁₈alkyl which        is substituted by E′ and/or interrupted by D′, C₆-C₂₄aryl,        C₆-C₂₄aryl which is substituted by G, C₂-C₂₀heteroaryl,        C₂-C₂₀heteroaryl which is substituted by G, C₂-C₁₈alkenyl,        C₂-C₁₈alkynyl, C₁-C₁₈alkoxy, C₁-C₁₈alkoxy which is substituted        by E′ and/or interrupted by D′, or C₇-C₂₅aralkyl, wherein        -   D′ is —CO—, —COO—, —S—, —O—, or —NR¹¹²—,        -   E′ is C₁-C₈thioalkoxy, C₁-C₈alkoxy, CN, —NR¹¹²R¹¹³,            —CONR¹¹²R¹¹³, or halogen,        -   G is E′, or C₁-C₁₈alkyl, and            -   R¹¹² and R¹¹³ are independently of each other H;                C₆-C₁₈aryl; C₆-C₁₈aryl which is substituted by                C₁-C₁₈alkyl, or C₁-C₁₈alkoxy; C₁-C₁₈alkyl; or                C₁-C₁₈alkyl which is interrupted by —O— and

B, D and E are independently of each other a group of formula

or a group of formula (24),with the proviso that in case B, D and E are a group of formula (24),they are different from A, wherein

-   -   k′ is 1,    -   l′ is 0, or 1,    -   r′ is 0, or 1,    -   z′ is 0, or 1, and    -   Ar⁵, Ar⁶, Ar⁷ and Ar⁸ are independently of each other a group of        formula

-   -   wherein one of X⁵ and X⁶ is N and the other is CR¹⁴⁰,    -   R¹⁴⁰, R^(140′), R¹⁷⁰ and R^(170′) are independently of each        other H, or a C₁-C₂₅alkyl, preferably C₆-C₂₅alkyl, which may        optionally be interrupted by one or more oxygen atoms.

Preferred polymers are described in WO2010/049321.

Ar¹ and Ar^(1′) are preferably

very preferably

and most preferably

Ar², Ar^(2′), Ar³, Ar^(3′), Ar⁴ and Ar^(4′) are preferably

more preferably

The group of formula

is preferably

more preferably

most preferred

R⁴⁰ and R⁴¹ are the same or different and are preferably selected fromhydrogen, C₁-C₁₀₀alkyl, more preferably a C₈-C₃₆alkyl.

A is preferably selected from the group consisting of

Examples of preferred DPP polymers comprising, preferably consistingessentially of, a polymer unit of formula (20) are shown below:

wherein

-   R⁴⁰ and R⁴¹ are C₁-C₃₆alkyl, preferably C₈-C₃₆alkyl, and-   n′ is 4 to 1000, preferably 4 to 200, more preferably 5 to 100.

Examples of preferred DPP polymers comprising, preferably consistingessentially of, a copolymer unit of formula (21) are shown below:

wherein

-   R⁴⁰ and R⁴¹ are C₁-C₃₆alkyl, preferably C₈-C₃₆alkyl, and-   n′ is 4 to 1000, preferably 4 to 200, more preferably 5 to 100.

Examples of preferred DPP polymers comprising, preferably essentiallyconsisting of, a copolymer unit of formula (22) are shown below:

wherein

-   R⁴⁰ and R⁴¹ are C₁-C₃₆alkyl, preferably C₈-C₃₆alkyl,-   R⁴² is C₁-C₁₈alkyl,-   R¹⁵⁰ is a C₄-C₁₈alkyl group,-   X′=0.995 to 0.005, preferably x′=0.4 to 0.9,-   y′=0.005 to 0.995, preferably y′=0.6 to 0.1, and-   x+y=1.

DPP Polymers comprising, preferably consisting essentially of, acopolymer unit of formula (22-1) are more preferred than DPP polymerscomprising, preferably consisting essentially of, a copolymer unit offormula (22-2).

The DPP polymers preferably have a weight average molecular weight of4,000 Daltons or greater, especially 4,000 to 2,000,000 Daltons, morepreferably 10,000 to 1,000,000 and most preferably 10,000 to 100,000Daltons.

DPP Polymers comprising, preferably consisting essentially of, acopolymer unit of formula

(with R40, R41 being alkyl, such as 2-hexyldecyl)or a copolymer unit of formula (21-1) are particularly preferred.Reference is, for example made to example 1 of WO2010/049321:

The dielectric layer comprises a dielectric material. The dielectricmaterial can be silicium/silicium dioxide, or, preferably, an organicpolymer such as poly(methylmethacrylate) (PMMA), poly(4-vinylphenol)(PVP), poly(vinyl alcohol) (PVA), anzocyclobutene (BCB), polyimide (PI).

Preferably, the dielectric layer comprises the present oxacycloolefinicpolymer.

The substrate can be any suitable substrate such as glass, or a plasticsubstrate. Preferably the substrate is a plastic substrate such aspolyethersulfone, polycarbonate, polysulfone, polyethylene terephthalate(PET) and polyethylene naphthalate (PEN). More preferably, the plasticsubstrate is a plastic foil.

Also part of the invention is a transistor obtainable by above process.

An advantage of the process of the present invention is that the presentoxacycloolefinic polymer is resistant to shrinkage.

Another advantage of the process of the present invention is that thepresent oxacycloolefinic polymer shows a high chemical and thermalstability. As a consequence, the process of the present invention can beused to prepare, for example, an organic field effect transistor,wherein the layer comprising present oxacycloolefinic polymer is thedielectric layer, wherein the electrodes on top of the dielectric layercan be applied by evaporation through a shadow mask.

Another advantage of the process of the present invention is thatpresent oxacycloolefinic polymer is soluble in an organic solvent(solvent A). Preferably, it is possible to prepare a 2% by weight, morepreferably a 5% by weight and most preferably a 8% by weight solution ofpresent oxacycloolefinic polymer in the organic solvent. Thus, it ispossible to apply present oxacycloolefinic polymer by solutionprocessing techniques.

Another advantage of the process of the present invention is that theorganic solvent used to dissolve present oxacycloolefinic polymer

-   -   (i) preferably has a boiling point (at ambient pressure) of        below 160° C., preferably below 150° C., more preferably below        120° C., and thus can be can be removed by heat treatment at a        temperature of below 120° C., preferably at a temperature in the        range of 60 to 110° C., and    -   (ii) preferably does not dissolve suitable semiconducting        materials such as diketopyrrolopyrol (DPP) thiophenes, and thus        allows the formation of a smooth border when applying the        present oxacycloolefinic polymer on a semiconducting layer        comprising diketopyrrolopyrol (DPP) thiophenes.

Another advantage of the process of the present invention is that allsteps of the process can be performed at ambient atmosphere, which meansthat no special precautions such as nitrogen atmosphere are necessary.

The advantage of the transistor of the present invention, preferably,wherein the transistor is an organic field effect transistor and whereinthe layer comprising present oxacycloolefinic polymer is the dielectriclayer and the semiconducting layer comprises a semiconducting material,for example a diketopyrrolopyrrole (DPP) thiophene polymer, is that thetransistor shows a high mobility, a high Ion/Ioff ratio and a low gateleakage.

The following examples illustrate the invention. Wherever noted, roomtemperature (r.t.) depicts a temperature from the range 22-25° C.; overnight means a period of 12 to 15 hours; percentages are given by weight,if not indicated otherwise. Molecular weight is as determined by gelpermeation chromatography, if not indicated otherwise. The glasstransition temperature is determined by differential scanningcalorimetry (DSC), using a Mettler-Toledo DSC 822E® with Mettler-ToledoStare® Software 9.10, closed standard aluminium crucible (40microliter), sample weighing range 4000-10000 mg, nitrogen 50 ml/min,temperature gradient:

-   -   first heating 20-300° C. with 20° C./min, followed by    -   cooling from 300-20° C. with 20° C./min, and    -   second heating from 20-300° C. with 20° C./min.

Further abbreviations:

-   Mw molecular weight as obtained by high temperature gel permeation    chromatography-   NMP N-Methylpyrrolidone-   PDI polydispersity (by high temperature gel permeation    chromatography)-   Tg glass transition temperature-   b.p. boiling point (at 1 atmosphere pressure)

EXAMPLE 1

a) Preparation of Monomer 1

100 g of p-isopropylaniline (1 eq, 0.74 mol) is added to a solution of122.9 g of exo-3,6-Epoxy-1,2,3,6-tetrahydrophthalic anhydride (1 eq,0.74 mol) in acetone and stirred for 2 h. The resulting precipitate isfiltrated, washed with acetone, dried and mixed with 27 g of sodiumacetate in 550 mL of acetic anhydride. The mixture is then stirred for 2h at reflux and cooled down at 0° C. The resulting precipitate isfiltrated, washed with water, recrystalized in methanol and dried toyield the corresponding 1 as a pure white solid. Yield=71%; ¹H-NMR(CDCl₃): δ (ppm) 1.18 (d, 6H), 1.56 (s, 2H), 2.79 (s, 2H), 2.94 m, 1H),3.03 (s, 2H), 5.42 (s, 2H), 6.59 (s, 2H), 7.20 (d, 2H), 7.33 (d, 2H).

b) Polymer P1

63 mg of(1,3-Bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(oisopropoxyphenylmethylene)ruthenium(0.5% mol, 100 μmol) is added to 2 g of 1 (1 eq, 18 mmol) in 15 mL ofanhydrous dichloromethane under Nitrogen. After being stirred for 4 h atreflux, 10 mL of anhydrous dichloromethane and 1 mL of ethylvinyletherare added. The mixture is poured in cold ethanol. The precipitate isfiltrated, dissolved in a minimum amount of dichloromethane and pouredin cold heptane. The precipitate is filtrated, dried to yield thecorresponding pure polymer P1 as a white solid. Yield=61% Mw=161kDa/PDI=2.1/Tg=228° C.

-   Sodium content 14 mg/kg-   Phosphore content 24 mg/kg-   Ruthenium content 117 mg/kg

EXAMPLE 2 In Analogy to Example 1, The Following Polymers are Prepared

a) Polymer P2:

-   -   Mw=46.5 kDa    -   PDI=1.46    -   Tg=238° C.

b) Polymer P3:

-   -   Mw=69 kDa    -   PDI=1.60    -   Tg=144° C.

EXAMPLE 3 Preparation of a Top-gate, Bottom Contact (TGBC) Field EffectTransistor Comprising a Gate Dielectric Layer of P1

Gold is sputtered onto poly(ethylene terephthalate) (PET) foil to forman approximately 40 nm thick film and then source/drain electrodes(channel length: 10 μm; channel width: 10 mm) are structured byphotolithography process. A 0.75% (weight/weight) solution of adiketopyrrolopyrrole (DPP)-thiophene-polymer (polymer 21-1 according toexample 1 of WO2010/049321:

in toluene is filtered through a 0.45 μm polytetrafluoroethylene (PTFE)filter and then applied by spin coating (15 seconds at 1300 rpm,acceleration 10.000 rpm/s. The wet organic semi-conducting polymer layeris dried at 100° C. on a hot plate for 30 seconds. A 8% (weight/weight)solution of P1 in Methoxypropyl Acetate is filtered through a 0.45 μmfilter and then applied by spin coating (1100 rpm, 60 seconds). The wetlayer film is pre-baked at 100° C. for 20 minutes on a hot plate toobtain a 365 nm thick layer. Gate electrodes of gold (thicknessapproximately 120 nm) are evaporated through a shadow mask on the P1layer. The whole process is performed without a protective atmosphere.

Measurement of the characteristics of the top gate, bottom contact(TGBC) field effect transistors are measured with a Keithley® 2612Asemiconductor parameter analyser.

The drain current I_(ds) in relation to the gate voltage V_(gs)(transfer curve) for the top-gate, bottom-contact (TGBC) field effecttransistor comprising a P1 gate dielectric at a source voltage V_(sd) of−20V (upper curves) is shown in FIG. 1.

The top-gate, bottom-contact (TGBC) field effect transistor comprising aP1 as gate dielectric shows a mobility of 0.36 cm²/Vs (calculated forthe saturation regime) and an Ion/Ioff ration of 5 E+5.

The drain current I_(ds) in relation to the drain voltage V_(ds) (outputcurve) for the top-gate, bottom-contact (TGBC) field effect transistorcomprising P1 at a gate voltage V_(gs) of 0V (squares), −5V (stars),−10V (lozenges), −15V (triangles), and −20V (circles) is shown in FIG.2.

EXAMPLE 4 Preparation of a Capacitor

A 8% (weight/weight) solution of polymer P1 as obtained in example 1b inMethoxypropyl Acetate is filtered through a 0.45 μm filter and appliedon a clean glass substrate with indium tin oxide (ITO) electrodes byspin coating (1100 rpm, 30 seconds). The wet film is pre-baked at 100°C. for 20 minutes on a hot plate to obtain a 490 nm thick layer. Goldelectrodes (area=3 mm²) are then vacuum-deposited through a shadow maskon the P1 layer at <1×10⁻⁶ Torr.

The capacitor thus obtained is characterized in the following way:

The relative permittivity ∈_(r) and the loss factor tg(δ)=∈_(r)″ arededuced from the complex capacity measured with a LCR meter Agilent4284A (signal amplitude 1 V). Current /Voltage (I/V) curves are obtainedwith a semiconductor parameter analyser Agilent 4155C. The breakdownvoltage is the voltage Ed where the current reaches a value of 1 μA. Thevolume resistivity ρis calculated from the resistance, sample thicknessand electrode surface.

In the same way, capacitors are prepared and investigated using polymers2 and 3. results are compiled in the below table.

ρ ε_(r) ε_(r) ε_(r)″ ε_(r)″ Ed Polymer [Ωcm] 20 Hz 100 kHz 20 Hz 100 kHz[V/μm] 1 2.5E+15 3.15 3.01 0.037 0.040 >190 2 1.9E+15 3.05 2.92 0.0370.022 >143 3 3.8E+15 2.87 2.76 0.029 0.025 171

EXAMPLE 5 Alternative Preparation of Polymer

a) Preparation of Monomer 2

100 g of p-isopropylaniline (1 eq, 0.74 mol) is added to a solution of122.9 g of exo-3,6-Epoxy-1,2,3,6-tetrahydrophthalic anhydride (1 eq,0.74 mol) in acetone. The mixture is then stirred for 2 h. The resultingprecipitate is filtrated, washed with acetone and dried to yield thecorresponding pure 2 as a white solid. Yield=87%

¹H-NMR (DMSO): δ (ppm) 1.19 (d, 6H), 2.67 (d, 1H), 2.79 (d, 1H), 2.83(m, 1H), 5.03 (s, 1H), 5.14 (s, 1H), 6.50 (m, 2H), 7.15 (d, 2H), 7.44(d, 2H), 9.60 (s, 1H).

b) Preparation of Monomer 3

182.4 g of 2 (1 eq, 0.63 mol) is added to 550 mL of acetic anhydride and27 g of sodium acetate (0.5 eq, 0.33 mol). The mixture is then stirredfor 2 h at reflux and cooled down at 0° C. The resulting precipitate isfiltrated, washed with water, recrystalized for methanol and dried toyield the corresponding pure 3 as a white solid. Yield=79% ¹H-NMR(CDCl₃): δ (ppm) 1.18 (d, 6H), 1.56 (s, 2H), 2.79 (s, 2H), 2.94 (m, 1H),3.03 (s, 2H), 5.42 (s, 2H), 6.59 (s, 2H), 7.20 (d, 2H), 7.33 (d, 2H).

c) Polymer P1′

80 mg of Bis(tricyclohexylphosphine)benzylidine ruthenium(IV) dichloride(0.5% mol, 100 μmol) is added to 5 g of 3 (1 eq, 18 mmol) in 15 mL ofanhydrous dichloromethane under Nitrogen. After being stirred for 5 h atroom temperature, 10 mL of anhydrous dichloromethane and 1 mL ofethylvinylether are added. The mixture is poured in cold ethanol. Theprecipitate is filtrated, dissolved in a minimum amount ofdichloromethane and poured in cold heptane. The precipitate isfiltrated, dried to yield the corresponding pure polymer 1′ as a whitesolid. Yield=61%

Mw = 128 kDa PDI = 3.4 Tg = 228° C. Na content 14 mg/kg P content 24mg/kg Ru content 117 mg/kg

BRIEF DESCRIPTION OF FIGURES

FIG. 1 shows drain current I_(ds) in relation to the gate voltage V_(gs)(transfer curve) for the TGBC field effect transistor comprising apolymer 1 gate dielectric at a source voltage V_(sd) of −20V (uppercurves).

FIG. 2 shows the output curves for the TGBC field effect transistorcomprising polymer 1 at a gate voltage V_(gs) of 0V (squares), −5V(stars), −10V (lozenges), −15V (triangles), and −20V (circles).

The invention claimed is:
 1. An electronic device containing at leastone dielectric material which comprises an oxacycloolefinic polymer,which comprises a polymer chain of the formula III

wherein n ranges from 3 to 100 000, each of R₂ to R₅ is selected fromhydrogen and C₁-C₄alkyl, and R is hydrogen, C₁-C₂₅alkyl,C₁-C₂₅haloalkyl, phenyl, phenyl-C₁-C₄alkyl, cyclopentyl, or cyclohexyl,wherein phenyl moiety or cyclopentyl or cyclohexyl moiety itself isunsubstituted or substituted by C₁-C₄alkyl, C₁-C₄alkoxy, OH, halogen. 2.The electronic device according to claim 1, wherein the oxacycloolefinicpolymer is prepared by Ru-carbene catalyzed ring-opening metathesispolymerization of a bicyclic oxaolefin.
 3. The electronic deviceaccording to claim 1, wherein the oxacycloolefinic polymer is present asa layer essentially consisting of the oxacycloolefinic polymer.
 4. Theelectronic device according to claim 1, wherein the oxacycloolefinicpolymer has a glass transition temperature, as determined bydifferential scanning calorimetry, above 90° C.
 5. The electronic deviceaccording to claim 1, wherein the electronic device is selected fromcapacitors, transistors such as organic field effect transistors, anddevices comprising said capacitor and/or transistor.
 6. The electronicdevice according to claim 1, further comprising a substrate andcomprising at least one further layer of a functional material in directcontact with the oxacycloolefinic polymer dielectric.
 7. The electronicdevice according to claim 6, wherein a layer of the oxacycloolefinicpolymer as a dielectric material is in direct contact with an electrodelayer and/or a semiconductor layer.
 8. The electronic device accordingto claim 6, wherein a layer of the oxacycloolefinic polymer as adielectric material is in direct contact with a semiconductor layer thatcomprises a copolymer of the diketopyrrolopyrrole class.
 9. Theelectronic device according to claim 1, wherein the dielectric materialis a dielectric layer in a printed electronic device.
 10. The electronicdevice according to claim 9, wherein the printed electronic device is acapacitor or an organic field-effect transistor.
 11. A process for thepreparation of an electronic device according to claim 1, the processcomprising; providing a solution or dispersion of the oxacycloolefinicpolymer of formula III in a solvent, and applying the solution or thedispersion in the form of a layer onto a substrate, an electrodematerial or a semiconductor, and drying said layer.
 12. The processaccording to claim 11, wherein the solution or the dispersion includesat least 8% by weight of the oxacycloolefinic polymer in solution. 13.The electronic device according to claim 1, wherein the oxacycloolefinicpolymer has a molecular weight, as determined by gel permeationchromatography, in a range of 10,000 to 1,000,000 g/mol.
 14. A gateinsulator layer comprising an oxacycloolefinic polymer comprising apolymer chain of formula III

wherein n ranges from 3 to 100 000, each of R₂ to R₅ is selected fromhydrogen and C₁-C₄alkyl, and R is hydrogen, C₁-C₂₅alkyl,C₁-C₂₅haloalkyl, phenyl, phenyl-C₁-C₄alkyl, cyclopentyl, or cyclohexyl,wherein phenyl moiety or cyclopentyl or cyclohexyl moiety itself isunsubstituted or substituted by C₁-C₄alkyl, C₁-C₄alkoxy, OH, halogen.